This is a program of research into brain behavior relationships that has entered its fourth phase. The main question addressed is the nature of the associative memory structure of the brain. Subhuman primate studies have suggested a cortico-subcortical organization for associative function; human clinical case material continues to be analyzed within the classical transcortical connection framework. The proposed work is discussed under three major headings, each of which portrays a technical competence developed for the current phase of the program. The first technical area uses a newly devised flexible discrimination apparatus for discrete trial analysis (DADTA IV). The purpose of this set of studies is to tie the primate lesion work back to the clinic where lesions in man gave rise to the program during Phase I. The second major technical heading involves the study of evoked electro-cortical activity and behavior. Macro and multiple micro electrodes implanted in the monkey cortex will be used to pursue the current finding of differential electrical brain activity when a monkey is selectively attending visual inputs. Experiments have been begun to relate these findings to children of various ages. The final major technical area uses unit receptive field analysis in the visual system of both curarized and freely-moving animals. Electrical stimulation of inferotemporal, parietal and motor parts of the monkey's brain will then be made in order to determine the changes in the receptive field that result. The pathways by which such changes can occur will be traced with autoradiographic techniques. The aim of these studies directly concerns the issues stated in the title of the proposal.